Having hooked you with the heading, it's see exactly what teletext is before backing up those wild and whirling words with facts and information. Don't skip ahead! It'll be worth the wait, I promise.

The BBC's Mode 7 uses a teletext display. It is produced by a special teletext chip which leaves most of the Beeb's 32K memory free for programs. Graphic displays in Mode 7 are created differently to the displays in the so-called graphic Modes. Teletext graphics characters use a 2 x 3 grid the same size as an alphanumeric character which gives them a rather chunky look. Colours and effects are produced by VDU codes which affect characters printed after them on the same line. In spite of the low resolution and seemingly restrictive programming methods, some amazing displays can be created and examples can be seen daily on the Oracle and Ceefax teletext information services.

Many Electron owners have long wished for a Mode 7. Not only would they then be able to design teletext screens but they could run BBC programs which utilise Mode 7. And they would have all that extra memory to play with. Too much to ask? Not now, so carry on reading, Electron owners. Just to keep you on tenterhooks a little longer, a quick word from our sponsor.

The teletext service, whose displays the Beeb's teletext chip is intended to compliment, is run by the television broadcasting authorities. It is a free service which broadcasts digital information along with the TV picture. This data can be read by a teletext decoder connected to a TV aerial and many television sets are now equipped with a teletext receiver. They provide a welcome relief from soap operas and sport.

Teletext information is broadcast in a series of pages, each one the equivalent of a Mode 7 screen. It gives you information about the weather, travel, news, TV programs, jokes, recipes and lots more. For example, the Micro Live programs are supplemented by pages of additional information. Teletext also offers free programs called telesoftware which can be downloaded into your computer if it has a suitable teletext adapter. Unfortunately, you can't download software through a teletext-equipped TV.

As the BBC's Mode 7 is compatible with a teletext display you only need a few more bits and bobs (and chips, etc) to turn the Beeb into a teletext receiver. The Morley Adapter does just that. Because the Electron does not have a built-in teletext chip, one is 'built-in' to the Electron adapters.

Now, here's where it starts to get interesting because the Electron adapters support teletext level II. This means that all those VDU commands which do nothing in the Beeb's Mode 7 actually have an effect in the Electron. For example, it permits black text on a coloured background, something I've always wanted to do on my Beeb - out of perversity, probably. Some people are never satisfied.

There are three versions of the adapter currently available: a BBC version, an Electron RGB version and an Electron UHF version. The difference will become clear in a moment. The BBC version plugs into the User Port and the Beeb's power supply. An optional PSU is available but the power drain is minimal. Software is available on ROM or disc (for loading into RAM) and is compatible with the Master.

As well as connecting to the RGB or UHF sockets, the Electron adapters also have a PCB on a flying lead which must be plugged into the Cartridge Plot. This is the equivalent of plugging into the Beeb's User Port and if you soldered a few wires to the protruding end of the PCB you would effectively have an Electron User Port. It could be used in a similar way to the Beeb's only the register address if &FC60 instead of &FE60. The Electron software is built-in to the adapter.

All adapters access teletext pages in a similar way. The first step, after plugging in, is to tune in to the stations. This is software-driven and will probably tune into the main channels automatically. If you are in a poor reception area you may need to use the fine tune option. This also lets youo tuen into other channels if, for example, you can receive more than four and it allows for any new teletext channels which may arrive in the future.

The channel data is saved to disc or tape for future use and must be loaded before the adapter will work. BBC users can blow this into their ROM as the relevant locations have been left unprogrammed (Morley will do this for you for £5 if you don't have an EPROM blower) or put it into their disc image.

Once you're tuned in, typing *TTEXT puts you into terminal mode. The main options from the menu screen enable you to save a selected page, dump the current page (text only) to a printer, download software, select a new channel, hold the page to prevent updating, reveal any hidden text, verify the page for errors and use OS (*) commands. You can, of course, just browse at leisure following a particular set of pages or branching from one to another. The nice thing about all this is that it doesn't cost you anything - apart from your licence fee. No telephone charges as you would incur with a modem.

To select a page you just enter the three-digit page number. This is shown on-screen along with the number of the current page being broadcast which is constantly updating. There is usually a few seconds delay before your page is reached but the fact that it's not costing you anything it mollifies your impatience.

Most of the options are self-explanatory but let's look at the downloading process in a little more detail as this will be of major interest to most potential users. It is actually very simple. Pressing * sets the download routine in motion and the program automatically selects the catalogue page and requests the relevant page number. Programs are loaded in blocks, each of which is checked for CRC errors. The program will cycle through the blocks until every one is error free. You are them prompted to hit Space to save it.

Most programs can simply be chained but there are special instructions in the software pages which tell you exactly how to run each one. Best to read them, too.

That's basically how teletext adapters work but you can do much more than just look at information and download software. Morley's terminal software contains almost 100 * commands - I don't know they managed to cram them all in. A lot of them are convenience functions such as *BBC1 and *ITV to select channels. Others such as *CITY, *FINANCE, *NEWS and *SPORT select the correct channel and page and display them in a loop.

When you really start to dig into the system you find commands to select and display pages, header information, the time and the date. More dedicated teletext buffs can involve themselves with the TSDP (Teletext Service Data Packet) and the reading of various codes and bytes in the page headers. A bit much perhaps for the average user but the hacker will be in his (or her) element. The latest edition of the manual details all the * commands with a line of explanation but it would be nice to know to exactly what use you can put some of the more exotic functions.

OSBYTE commands can be used to program the adapter. *FX50 is used to write to it and a Register Map is given in the manual so you can see which bits and bytes do what. OSWORD can be used to read and write data to it, too. Sample programs illustrate how these can be used.

For the less technical user, the * commands can be used from Basic and you can write programs which make use of the information transmitted by teletext. Morley have a utility disc at £5.95 (for the BBC) which includes screen and text dump programs, a page finger and spooler and a TV Times generator. The latter picks up information from the TV pages and prints it out. You can pick up a lot of information from these programs to help you write your own.

Morley also produce DESIGN 7, a Mode 7 screen designer at £8.95. It's a must if you want to create Mode 7 screens and it complements the adapter perfectly because you can load in teletext screens and modify them. Special functions give you various sixes of large text; they let you create instant boxes and frames; offer cut and paste options and there is even a line-drawing facility. This is one of the most comprehensive and easy to use Mode 7 screen design programs I have yet seen and great value for money.

Not content with that, Morley have also produced DESFAX 7 (£24) which lets you design Mode 7 screens (it contains the DESIGN 7 program) and store up to 100 of them on a 40 track disc (200 on 80 track). The pages can be read in and displayed in a pre-selected order and for a predetermined time to produce a form of animation. Text can be printed at variable speeds, ideal for creating instruction screens or shop displays. It can even help run your own teletext service and, again, this interfaces with the adapter. The demo supplied is certainly very impressive.

Now, for all you patient Electron readers, here's the news about the Mode 7 emulator. BBC owners keep reading, too, because there's also something here of interest to you.

The Electron adapters have a built-in level 2 teletext chip. You enter Mode 7 by typing *MODE7 and away you go. The screen image is stored in RAM in the adapter and the new Mode should enable you to run 90% of BBC Mode 7 programs. It doesn't work exactly like the BBC's Mode 7 so I'll list the differences first and then move on to the things it lets you do that you can't do on a Beeb.

The first noticeable difference is in its method of updating the screen. Software scrolling would apparently take too long so the screen does not scroll but clears when full, after a keypress, and fills again - a la Sinclair. As the screen is in RAM in the adapter, any program using screen pokes will not work but all legally-written software will.

Programs can not be edited in the new Mode. You can enter new lines, of course, but the cursor and copy keys do not work although the cursor keys will function from within a program. For cursor editing you must revert to Mode 6 and go back to Mode 7 for running. This will only cause problems if your program is so long it can not be held in memory in Mode 6. Extra workspace is required to hold variables when you run a program and this will be gained when you revert to Mode 7 so you should be able to edit all but the very largest programs this way.

At the moment, the Electron adapters only work with tape because of a clash over workspace with the ADFS but it is hoped this will soon be sorted out and a disc version made available. If you're thinking of waiting before splashing out - don't! All software updates are free so you can familiarise yourself with the tape system and move up to disc at a later date.

Now let's look at the goodies. As mentioned earlier, the Electron chip can produce more teletext characters than the Beeb chip. Some code produce special characters designed with the definition of the alphanumeric characters. There are also additional controls so that, for example, after issuing a VDU141 command for double height text, all following text automatically appears in double height. You don't have to print the string twice. Electron owners can still pass on their screen designers to Beeb owners, but, of course, the new level 2 characters will not be displayed.

If you plump for the UHF adapter you get an added bonus. You will be able to overlay teletext designs onto a video screen and switch between video and teletext at will. The overlays can take many forms. You can superimpose a teletext box on the screen and you can frame the video picture inside a box. Any boxed area can be written in as usual. Simple software would enable you to, for example, define a series of boxes each holding text and stipulate their position on the screen. They could then be overlaid in order by pressing a key.

The manual only gives one simple program to demonstrate all this but the potential for titling videos and producing subtitles is all there at an incredible saving over the price of dedicated video/titling hardware and software. This is in addition to a teletext adapter and the extra memory made available by Mode 7.

If Beeb owners are feeling a little left out now, they'll be cheered to know that this adapter can also be made to work on their machine. All it requires is for the PCB which plugs into the Electron Cartridge Port to be removed and a BBC User Port plug substituted. Morley say they will do this for any interested parties. At the moment, however, the Beeb software has a few more functions than the Electron software so a phone call to see exactly what you're getting would be wise.

Morley are currently working on a digitiser with 4096 colours and full video processing so you will be able to digitise a video shot, save it and edit it. It will have a multiple page store facility (in RAM) so you won't have to wait while the teletext pages come around and you will be able to perform all the overlay functions mentioned above. It will be "very cheap" but not available until 1987. Something to look forward to, though.

Acorn's teletext adapter had the market to itself for a couple of years but it was quite expensive and made life complicated for the user, especially when downloading software. Even now a software patch must be used (available on telesoftware) before downloading a program. BBC Publications, however, have brought out a replacement 16K ROM called the Advanced Teletext System ROM which doesn't need the patch and which seems altogether a lot more user-friendly. If you have an Acorn adapter it may be worthwhile dusting it off but it still won't give you screen overlays and it won't be much use to Electron owners either.

Morley's BBC adapter costs £74.45 but you must also buy the software which costs £24.95 on ROM or £23.95 on disc. The optional PSU is £9.95. The Electron RBG adapter is £149.95 and the UHF adapter is £177.90. Morley will customise an Electron UHF adapter to fit a BBC (getting complicated, isn't it?) for £175.

As you may have guessed, I am very impressed with the Morley adapters although I would have liked to have seen even more information in the manual (the sign of an Infomaniac, so I've been told!) and an on/off switch. A most worthwhile and fascinating addition to your BBC and I just don't know how an Electron owner could resist one: teletext, Mode 7, 32K memory and video overlays...